Question 1191757
each has probability of 1/7 of being chosen
add the (squares-1)  and divide by 7 to get the expected value
-3,0,0,5,5,5,11
the sum is 23
the expected value is 23/7 or 3.29
variance is sum (square-mean)*prob.
so we have -6.292+3.29^2*2-4+1.71^2*3-4+7.71^2-4
-6.292
6.8241*2
4.7723*3
55.4
that sum is the variance or 77.07
sd is sqrt(V)=8.78